The linear guide apparatus is provided with a guide rail, a slider, and plural rolling elements. The guide rail and the slider include rolling grooves (or rolling faces when the rolling elements are “rollers”), respectively, disposed opposing each other and forming a rolling passage of the rolling elements. The slider further includes a return passage of the rolling elements and a direction changing path for communicating the return passage with the rolling passage. Then, a circulation path of the rolling elements is configured with the rolling passage, the return passage, and the direction changing path. By circulation of the rolling elements through the circulation path, one of the guide rail and the slider is relatively and linearly moved to the other thereof.
In addition, the linear guide apparatus is provided with separators, each of the separator including a spacer disposed between adjacent rolling elements and an arm portion (i.e., guide portion) secured to the spacer and extending in an arrangement direction of the rolling elements, and a guide groove to guide the arm portion is formed in the circulation path of the rolling elements, in some cases. In such cases, the rolling elements move through the circulation path with being held or accommodated in the separators, and the arm portions of the separators moves along the guide groove.
PLT 1 discloses that the slider is configured with a body (i.e., block body), a resin circulation path forming body, and an end cap (i.e., side cover). The body is configured with leg portions respectively arranged on both sides in a width direction of the guide rail, and a trunk portion to connect both of the leg portions, and the rolling grooves are respectively formed on the inner sides of the leg portions.
As the resin circulation path forming body, PLT 1 discloses that a member (i.e., resin frame) is provided for each of the leg portions, the member being integrally formed of a retaining portion for retaining the rolling elements on the rolling face (i.e., load ball passage configuring portion extending along both side rims of the rolling groove), an inner circumference guiding portion (i.e., return guide) of the direction changing path, and a plate-shaped portion to be brought into contact with both end faces of each of the leg portions. Additionally, the end cap is secured to the end face of the body via the plate-shaped portion.
Further, in the end cap, an accommodating recess portion for accommodating the plate-shaped portion is formed in a uniform depth. PLT 1, however, does not disclose the plate-shaped portion being provided with an oil supply path forming groove for forming an oil path between the plate-shaped portion and the end cap.
PLT 2 discloses a retainer being provided for each of the leg portions of the slider body, the retainer being integrated with the plate-shaped portion to be brought into contact with both end faces of the body (except for a central portion in the width direction of the trunk portion), and a retaining portion disposed on the inner face of each of the leg portions and retaining the rolling elements on the rolling face, and the oil supply path forming groove is provided on an end cap side face of the plate-shaped portion. In addition, an oil supply opening penetrating through the end cap in a thickness direction at the central portion of the trunk portion of the end cap, and the oil supply path forming groove extending to both sides of the oil supply opening is formed on an abutting face abutting with the slider body.
Furthermore, on a body side face of the end cap, a face lower than the abutting face is formed as a disposition face of the plate-shaped portion of the retaining portion. Accordingly, by securing the end cap to the body on which the retainer is attached, the plate-shaped portion of the retainer is disposed on a plate-shaped portion disposition face of the end cap, so that the oil supply path forming groove of the end cap and the oil supply path forming groove of the plate-shaped portion are communicated with each other to form an oil supply path from an oil supply opening to the direction changing path.
In the configuration of PLT 2, however, when an interval between the plate-shaped portion disposition face of the end cap and the abutting face is smaller than the thickness of the plate-shaped portion of the retainer, a gap is generated at a location where the plate-shaped portion is not present between the end cap and the trunk portion of the body. Hence, the lubricant easily leaks.